Systems and methods for soft data utilization in a solid state memory system

Abstract

Systems and methods relating generally to solid state memory, and more particularly to systems and methods for recovering data from a solid state memory. An example data processing system includes a first circuit operable to yield a modified soft data set from a data set accessed from a solid state memory device, and a second circuit operable to apply a data decoding algorithm to the modified soft data to yield a decoded output.

What is claimed is: 
     
         1 . A data processing system, the system comprising:
 a first circuit operable to:
 yield a modified soft data set from a data set accessed from a memory device, the data set including an original soft data having a first number of bits per element, and the modified soft data set having a second number of bits per element; 
 apply a transfer function to yield an interim data set; and 
 force the value of any element of the interim data set that falls outside of a range of the second number of bits per element to equal a nearest extreme of a range to yield the modified soft data set. 
   
     
     
         2 . The data processing system of  claim 1 , further comprising a second circuit operable to apply a data decoding algorithm to the modified soft data set to yield a decoded output. 
     
     
         3 . The data processing system of  claim 2 , wherein the data decoding algorithm is a low density parity check decoding algorithm. 
     
     
         4 . The data processing system of  claim 1 , wherein the transfer function is a non-uniform transfer function. 
     
     
         5 . The data processing system of  claim 4 , wherein the non-uniform transfer function is operable to decrease a probability indicated by a first portion of an original soft data corresponding to the data set, and to increase a probability indicating by a second portion of the original soft data. 
     
     
         6 . The data processing system of  claim 5 , wherein the first portion of the original soft data exhibits a lower probability than the second portion of the original soft data. 
     
     
         7 . The data processing system of  claim 1 , wherein the data processing system is implemented in an integrated circuit. 
     
     
         8 . The data processing system of  claim 1 , wherein the data processing system further comprises:
 the memory device is a solid state memory device operable to maintain the data set;   wherein the data processing system including the solid state memory device is implemented on an integrated circuit.   
     
     
         9 . The data processing system of  claim 8 , wherein the memory device is a solid state memory device. 
     
     
         10 . The data processing system of  claim 2 , wherein the first circuit comprises a soft data modification circuit ;  and the second circuit comprises a data decoder circuit. 
     
     
         11 . The data processing system of  claim 1 , wherein the data processing system further comprises:
 a soft data generation circuit operable to generate an original soft data corresponding to the data set.   
     
     
         12 . A method for recovering data from a memory, the method comprising:
 generating a modified soft data set from a data set accessed from a memory device, the data set including an original soft data having a first number of bits per element, and the modified soft data set having a second number of bits per element;   applying a transfer function to yield an interim data set; and   forcing the value of any element of the interim data set that falls outside of a range of the second number of bits per element to equal a nearest extreme of a range to yield the modified soft data set.   
     
     
         13 . The method of  claim 12 , further comprising:
 generating a decoded output from the modified soft data set using a data decoding algorithm.   
     
     
         14 . The method of  claim 13 , wherein the data decoding algorithm is a low density parity check decoding algorithm. 
     
     
         15 . The method of  claim 12 , wherein the transfer function is a non-uniform transfer function. 
     
     
         16 . The method of  claim 15 , wherein the non-uniform transfer function is operable to decrease a probability indicated by a first portion of the original soft data, and to increase a probability indicating by a second portion of the original soft data. 
     
     
         17 . The method of  claim 16 , wherein the first portion of the original soft data exhibits a lower probability than the second portion of the original soft data. 
     
     
         18 . The method of claim , wherein the memory device is a flash memory device, the flash memory device operable to hold multiple bits of data in each memory cell of the flash memory device. 
     
     
         19 . A memory system comprising:
 a memory device operable to maintain a data set, the data set including an original soft data having a first number of bits per element; and   a first circuit operable to:
 yield a modified soft data set from the data set, the modified soft data set having a second number of bits per element; 
 apply a transfer function to yield an interim data set; and 
 force the value of any element of the interim data set that falls outside of a range of the second number of bits per element to equal a nearest extreme of a range to yield the modified soft data set. 
   
     
     
         20 . The memory system of  claim 19 , wherein the memory system further comprises:
 a second circuit operable to apply a data decoding algorithm to the modified soft data set to yield a decoded output.